Piston ring



July 17, 1923. 1,462,043

J. E. NORWOOD PISTON RING Filed May 27, 1918 m /6 I5 6 A? J'nvenior vJEZVZI yg r attorney Patented Jaly 17, 1923. I

UNITED STATES:

i JOHN E. NORWOOD, OF BALTIMORE, MARIL'AND.

rrs'ron nme.

, Applicationflled m 21,

To all whom it may concern: 7

Be it known that I, JOHN E. Nonwoon, a

citizen ofthe United States, residin at Baltimore, in the countyofBaltimore, tate of Maryland, have invented certain new and, usefulImprovements in Piston Rings; and I do hereby declare the following tobe a full, clear, and exact description of the invention, suchas willenable Others skilled in the art to which it appertains to make and usethe same. i

The present invention relates to new and useful improvements in pistonpackings', more particularly of the type disclosed-in my copendingapplication filed June 21, 1917, Serial No. 176,177, and particularlyadapted for packing pistons of the combustion cylinders of explosiveenginw. 4

As in my co-pending application, the essential feature of the presentinvention, is the provision of a packing ring structure which, isexpansile in nature both radially and laterally, to fit againsttheinnerperiphery of the cylinder and also to fit against both side walls of thepiston groove in-which it is disposed whereby to prevent leakagethrough-the groove about the inner portion of the ring. To accomplishthis essential feature, a pairof radially expansible ring sections areprovided, in cam. engagement whereby the limitation'of expandingmovement of the larger ring sections by engagementwith the cylinder wallwill procure a lateral relative movement of the sections for sealingengagement with the sides of the piston groove.

' I have found in practice that this lateral sealing action of thepiston ring structure against the side walls of the pistongroove isimpaired by the high pressure within the cylinder on combustlon, whichenters the space between the body of the piston and the cylinder walls,at the head portion of the piston and exerts a force radially on thesmallerpacking .ring section, compressing the section againstits'natural expansible resiliency, and thusdestroying the sealingpressureexerted against the side wall's'of the piston groove through thecam action of such resiliency, Therefore the particular 1918. 7 SerialN0. 236,860.

object of my present invention is to lessen the contractile action ofvthe combustion pressure in the cylinder upon the smallen laterallyacting section of my ring structure, and I purpose to accomplish thisohpct by so arranging the smaller ring section,

and '50 forming its surface which is exposed to combustion pressure inthe cylinder, that the force exerted by such pressure is directedobliquely to the direction of expansile. and contractile movement of thering section, and toward the adjacent wall of the piston groove so thatthe resultant inward force on thepiston ring is exerted through the ringagalnst said wall, to bind the ring 66 against compressive influence.

In the accompanying drawings:

Figure 1 is a sectional view taken longitudinally through acylinder andpiston of an explosive engine, having a ring structure 70 embodying thepresent invention disposed in the packing grooves thereof.

I F gure 2 1s an enlarged detailed sectional view taken transverselythrough one side of the ring and adjacent cylinder and piston portions.1 v

Figure 3 is a perspective view showing the ring cut in two. r 7Referring now more particularly to the accompanying drawings, 5designates the cylindenof an explosive engine, having a closed head 6and having slidable therein a piston 7, provided with the usual annularpacking grooves 8 in its periphery, each. groove being of the usualrectangular shape in cross sectlon afi'ording parallel-side wallsagainst which my improved packing ring is adapted to expand laterallyfor sealing engagement therewith. As in my said co-pending applicationeach packing ring iscomposite in nature including a pair of'annularsections 9 and. 10, and the section 9 is preferably of the same form asshown in'my said co-pending application, being of greater ex-. ternaldiameter than the section 10 and also having a substantially greatergeneral width,

which is nearly equal to the width of itspiston groove 8'. The member 9is beveled from cut cam face 13, its ends being preferably provided witha lap joint 14. The section is disposed at the cylinder head side 11 ofthe sectlon 9 and is provided with a beveled peripheral face 15, theinner portion of which is urged by the resiliency of the section intocam engagement with the undercut face 13 of the section 9, whoseresilient expansion is limited by the wall of the cylinder and thus theresilience of the section 10 serves to urge both sections into sealingengagement with the sides of the packing groove. The beveled peripheralface of the section 10 meets the outer face 16 of said section at anacute angle, and preferably at a line substantially coincident with thejuncture of the adjacent side face of the groove and the periphery ofthe piston.

The expanding action of the ring sections for sealing engagement withthe wall of the cylinder and with the sides of the packing groove, isthus the same as in my aforemen' tioned patent. When, however, thepresent ring structure is subjected to combustion pressure passingbetween the piston andcylinder, the force of such pressure is :exertedagainst the side face 11 of the'majfor ring section 9 will only serve topress it more firmly against the groove side with which it is in sealingengagement. At the same time, the pressure will exert a force againstthe ring section 10 tending to compress said section against theexpanding force of its natural resilience, but by reason of the bevel ofthe outer portion of the peripheral face 15 of the section, such forcewill be exerted obliquely toward the side of the packing groove withwhich the section is in sealing engagement and not exerted directlyinward,

as would be the case with all former structures for simultaneously"effecting both aradial and lateral expansion of a composite acking ringwith which I am acquainted. bus the resultant of forces would beobliquely against the side of the packing groove with which the sectlon10 is normally 1n sealing engagement, to birid the section against saidside of the groove and to prevent its inward movement under influence ofcombustion pressure. While the peripheral face 15 of the ring section 10has been shown as provided witha single bevel, transversely flatthroughout said face, it is obvious that any formation of thissurfacewhich will procure a lateral camming action between the sections andwhich will procure a lateral direction of the force of combustionpressure exerted against its outer portion, may be employed.

I am aware that consideration has heretofore been taken of the action ofworking pressure in a cylinder upon the sections of a entire peripheralsurface and having the inner portion of that beveled surface in cam.

cember 29, 1903,- but in the structure of this.

patent an entirely different and opposite. op-

eration is rocured, since it is the primary object of wans structure toprovide for a lateral compression of the piston ring by the action ofworking pressurein the cylinder, this compression-effecting a radialexpansion of the normally inoperative ring, and exposing one side of thepacking groove whereby gas could escape around the interior of the ringupwardly behind the piston through the joint of a ring section orbetween the other side of the groove and its adjacent ring section. Oneof the rings of Swan is contractile, while the other is solid and has noresiliency. Thus the patent to Swan compasses neither the object, norprovides the structure of my improved packing ring, which comprises apair of sections. both resiliently expansible in nature.

What is claimed is: y

1. The combination with the cylinder of an explosive engine and aperipherally grooved piston therein, of a com osite ring comprising aradially expansib e annular section within and of less width than thegroove, and projecting from the groove into peripheral contact w1th thecylinder wall and having one end face contacting with a, side wall ofthe groove and its other end face beveled to its inner periphery, thering comprising also a second annular radially expansible sectiondisposed between and contacting with the face of said bevel and theother side wall of the piston groove, the face of the second sectionthat contacts with the beveled face of the first section being ,conlcaland continuous to the peripheryof the piston where it meetsthe'corresponding end wall of the section.

2. The combination with the cylinder of an explosive engine and aperipherally I grooved piston therein, of a composite ring comprising aradially expansible annular posed against said side wall, the outerperiphery of the second section being beveled throughout its width tothe angle of said bevel of the first section against which it isslidably disposed, said bevel and-end face of the second section meetingsubstantially at the periphery of the piston and the bevel of the secondsection being greater in width In testimony whereof, I afiix mysignathanthat of the first section whereby a porture, in the presence of twowitnesses. tion of the bevel of the second section is at all timesaccessible to gas pressure between i JOHN E. NORWOOD. 5 it and the wallof the cylinder, in the direc- Witnesses:

tion of the groove Wall with which the'sec- J. A. MORIARTY,

0nd section contacts. EDWARD M. CoLBER'r.

